The present invention relates to trailer having a bed or box which automatically tilts, or dumps, upon the trailer being moved rearwardly.
Tilting, or dump, trailers are trailers which have a bed or body portion configured for carrying cargo and for tilting in order to offload, or dump the cargo. Dumping trailers are useful in that they offer a cargo-emptying feature without requiring a dedicated vehicle, such as a dump truck. A dump trailer can be used as needed by attaching it to a tow vehicle, such as a conventional truck, tractor, pick-up truck, sport utility vehicle (SUV), automobile, etc. Once the desired cargo has been hauled and dumped using the trailer, the trailer could then be detached from the tow vehicle, and the tow vehicle is then unencumbered and free to be used for other purposes.
In conventional dump trailers, the dumping mechanism is powered by a separate power source, such as a hydraulic or electric lift mechanism. Such mechanism adds weight and expense to the trailer, and also complexity. However, such a power mechanism is oftentimes required due to the weight of the load in the trailer, the load being prohibitively heavy for allowing the trailer to be tilted upwardly and dumped by hand.
Various types of dump trailers have been patented. U.S. Pat. No. 3,189,387, issued Nieto, Jr., discloses eccentric rim members which are mounted in front of trailer wheels, and which rotate in a manner that lifts the trailer into a dumping position as a trailer is pulled forwardly. U.S. Pat. No. 6,238,166 B1, issued to Collier, discloses a utility trailer with selectively deployable chains. Upon deployment of the chains and backing of the trailer, the tires engage the chain, and the trailer moves into a dumping position.
U.S. Pat. No. 5,544,944, issued to Keech; U.S. Pat. No. 4,711,499, issued to Fortin; U.S. Pat. No. 1,894,320, issued to Muchenberger-Wittlinger; and U.S. Pat. No. 4,511,181, issued to Schantz, all disclose tilting trailers that pivot at the end of a tow bar. In particular, the Keech patent discloses uses of a tilt lock mechanism, and the Fortin patent discloses a sliding hinge for dumping upon rearward movement. The Schantz patent allows for storage of a trailer in a vertical position.
Another desirable feature in a dump trailer is to provide a trailer which does not have to be detached from the tow vehicle in order to perform the dumping operation. Additionally, if such dumping could take place without requiring a separate, powered mechanism, such would be a further advantage.
It is, therefore, an object of the present invention to provide a tilting, or dumping, trailer which does not require an auxiliary power unit or other power mechanism in order to perform the dumping function.
Another object of the present invention is to provide a dumping trailer which may remain attached to a tow vehicle during a dumping operation.
A further object of the present invention is to provide a dumping trailer which may be dumped automatically by backing up the tow vehicle, with the trailer attached thereto.
A still further object of the present invention is to provide a dumping trailer which, after being moved to the dumping position, may be returned to its normal, cargo-hauling position, by pulling the tow vehicle forward.
Yet another object of the present invention is to provide a dumping trailer which may be tilted to a vertical position, and beyond vertical, during the dumping operation.
A still further object of the present invention is to provide a method of operating a dumping trailer.
Yet another object of the present invention is to provide a dumping trailer, wherein the dumping feature may be activated and deactivated by the user from the front-end of the trailer.
Generally, the present invention includes a trailer having a draw bar and coupler for attachment to a hitch of a tow vehicle, the trailer comprising a bed connected to a frame for pivotal movement with respect to the draw bar. The bed or other load carrying structure is movable between a generally horizontal, hauling position and a tilted, dumping position. The bed includes a forward portion adjacent the draw bar and a rearward portion opposite the forward portion. An axle is connected to the frame to which wheels are attached. Blocking members contact the axle as the tow vehicle moves rearwardly, the blocking members being movable between a blocking position, for contacting the ground to substantially block rearward movement of the frame as the trailer is moved rearwardly, and a retracted position, wherein the blocking members are substantially out of contact with the ground. Upon the blocking member being moved to the blocking position and the bed being in the hauling position, and upon the trailer being moved rearwardly, the bed pivots to the dumping position.
More specifically, the present invention includes a method of tilting a trailer and a tilting/dumping trailer having a mechanism wherein the blocking members are preferably stands having rocker portions thereon, the stands being pivotally attached to the trailer behind the trailer""s wheels. The stands are normally maintained in an upward position so as to provide adequate ground clearance for the trailer during use. When it is desired to dump the trailer, the user, from the front-end of the trailer, activates the stands to allow them to pivot downwardly for contact with the ground.
Activation of the stands is accomplished through use of a release mechanism, such as a chain and pin arrangement, or through the use of a linkage, straps, or the like, which preferably allow the stands to be released by the user, as mentioned above, while the user stands at the forward end of the trailer.
Locking mechanisms are provided which engage a forward portion of the trailer, and these locking mechanisms, in a preferred embodiment, are locking spring pushpins. These pushpins are released in order to allow the trailer bed to pivot with respect to the draw bar of the trailer. Once the stands have been lowered to the ground, upon backing up of the vehicle, the stands act as fulcrums about which the bed pivots, and actually cause the wheels of the trailer to be lifted off of the ground during backing. As the wheels are lifted off of the ground, the stands bear the weight of the trailer and its load. This forces the stands downwardly to substantially fix them from sliding with respect to the ground as the trailer is backed up. Upon continued backing of the vehicle, the trailer bed will begin tilting upwardly, and this allows for the contents of the trailer to be dumped.
It should be noted that as the bed tilts, its rear edge contacts the ground, and at this point, the bed itself becomes a ramp for allowing riding mowers, all terrain vehicles, go carts, tractors, etc. to be driven or otherwise loaded onto bed, if desired.
In order to return the trailer cargo bed back down to its normal position, the tow vehicle is moved forward such that the draw bar of the trailer pulls the trailer forward, thereby pivoting the trailer bed to a generally horizontal position. At this point, the wheels of the trailer may move freely, and the stands may be retracted, again, preferably from the front of the trailer, in order to prevent the stands from dragging on the ground during use of the trailer.
The trailer of the present invention includes a draw bar having a unique configuration which allows the trailer to be dumped without requiring it to be unhitched from the tow vehicle. This is allowed by virtue of the geometry of the draw bar, which includes angled portions for allowing the trailer to be moved to the dumping position, and returned to the normal, home, position while still hitched to the tow vehicle.
Accordingly, the trailer of the present invention requires no powered dumping mechanism, auxiliary or otherwise. This eliminates the need for power supply mechanisms, which are generally power take-off (PTO) hydraulic mechanisms, drawing motive power from the tow vehicle, or electric-hydraulic mechanisms, which require use of an electrically-powered hydraulic pump.
Further, typical dump trailers, because of their need for separate power devices for performing the dumping operation, must generally include increased structural support for supporting such dump mechanisms, which in turn adds weight and cost to the trailer. This weight and cost is in addition to that of the powered dumping system itself.
The trailer of the present invention, by eliminating the need for a powered dumping mechanism, can be made to be relatively lightweight and easy to move around by hand, thereby allowing enhanced maneuverability of the trailer in tight areas.
Because the trailer of the present invention requires no additional power source, such as an electrical hook-up or a hydraulic power take-off, to connect to the tow vehicle""s PTO system, the trailer can be used with almost any vehicle having an ordinary trailer hitch.
Moreover, by virtue of the design of the trailer of the present invention, the bed of the trailer is preferably elevated, compared to other trailers, thereby allowing easy access at the rear and sides for loading or off-loading with conventional lift trucks, such as forklifts, making the trailer attractive for use to business owners and, in particular, to the construction industry.